Top national brands have signed up for AmEx's new program with Twitter, the partnership unveiled Tuesday that allows consumers to get cash back by syncing their credit card and social media accounts. Best Buy, McDonald's, Whole Foods, and Zappos are just a smattering of the merchants that jumped at the opportunity to offer deals at launch. Unfortunately, the deals they're expected to promote to followers are not nearly as innovative as the novel platform they'll be running on.

As on Foursquare, which offers a similar AmEx program, consumers can earn credit back by interacting with a brand—say, $20 back after spending $75 for tweeting a certain hashtag or checking in at a location. This spend-some-get-some model is simple and accessible, but Twitter chief revenue officer Adam Bain believes brands and merchants are in the nascent stages of learning how to market consumers on social platforms. "This is just the beginning," he says. "You're going to see a ton of creative examples of people building on this platform—this is not just about giving people a deal or discount."

We've recently covered the socializing of credit, including a deep look at Twitter's AmEx deal:

What might these ads look like in the future then? Bain couldn't go into much detail, promising that we'd understand more when Twitter and AmEx show off the partnership at SXSW. But he did give a hint about where the advertising product is headed.

"In general, a lot of the [ads] have been focused on traditional percentage-off deals, but what's exciting about this opportunity is actually to bring access to content and other things to the platform," Bain teases. "Certainly deals, offers, and discounts will be a part of it, but we think the idea around access or other opportunities will be huge."

Perhaps this means offering access to exclusive rewards or products. AmEx cardholders often gain access to entertainment rewards such as travel deals or concert tickets; perhaps its partnership with Twitter will be an extension of those programs. AmEx, for example, will be holding a Jay-Z concert at SXSW, so perhaps we can expect that to play into this style of promotion.

Regardless of what brands come up with, Bain says the partnership is all about sales—both online and offline. Ultimately, this is what most distinguishes Twitter's platform with Foursquare's. While users on Foursquare might earn a one-off reward for checking in at a bar—a one-on-one interaction between merchant and consumer—there is a viral nature to how Twitter users earn rewards: by retweeting hashtags with followers, which could potentially propel a brand's ad to become a trending topic.

It's not so much a loyalty program as it is an advertising tool—a way to convert a brand's followers into an army of marketers. The rewards consumers can earn are virtually endless because the reward is automatically loaded to one's AmEx card, allowing consumers to just as easily buy groceries in store at Whole Foods or DVDs online at Amazon. "Buying directly from tweets will be huge," Bain predicts. In that sense, the platform is about driving sales—not just about driving foot traffic, as it is primarily with Foursquare's partnership. (In other words, you can retweet a hashtag from Zappos to earn a reward, but you can't check in to the online merchant.)

That's why Bain refers to the promoted tweet as the "atomic unit" of the company's ad strategy—a platform that will lead to "interesting transactions between consumers and merchants," he says.

"Ultimately, it allows a merchant to track the ROI from tweets, and allows them to better understand how Twitter drives visitors and commerce for their business."

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